WDPN32 PGTW 122100
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 16W (PODUL) WARNING NR 024//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 22.0N 123.4E
   INITIAL INTENSITY: 85 KTS
   GEOGRAPHIC REFERENCE: 213 NM SOUTH-SOUTHEAST OF TAIPEI, TAIWAN
   MOVEMENT PAST 6 HOURS: WEST-NORTHWESTWARD AT 15 KTS
   SIGNIFICANT WAVE HEIGHT: 36 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS TYPHOON
16W (PODUL) WITH A RAGGED EYE SURROUNDED BY VIGOROUS BURSTS OF DEEP
CONVECTION. CLOUD TOPS AROUND THE EYEWALL HAVE SIGNIFICANTLY COOLED
AT 122000Z, SUGGESTING FURTHER INTENSIFICATION BEFORE LANDFALL.
ANIMATED RADAR IMAGERY FROM TAIWAN REVEALS A WELL-DEFINED EYE
FEATURE TRACKING WEST-NORTHWESTWARD AND QUICKLY APPROACHING THE
SOUTHEASTERN COAST OF TAIWAN. A 121719Z AMSR2 89 GHZ MICROWAVE
IMAGE SHOWS THAT THE NORTHERN PORTION OF THE EYE CONTINUES TO BE
FRAGMENTED, LIKELY DUE TO THE NORTHEASTERLY SHEAR ACTING ON THE
SYSTEM. THE 37 GHZ VERSION OF THE SAME IMAGE SHOWS A WELL-DEFINED
MICROWAVE EYE FEATURE AT THE LOWER-LEVELS. ENVIRONMENTAL ANALYSIS
INDICATES THAT 16W IS IN A FAVORABLE ENVIRONMENT CHARACTERIZED BY
MODERATE WESTWARD AND EQUATORWARD OUTFLOW ALOFT, LOW TO MODERATE
(15-20 KTS) VERTICAL WIND SHEAR, AND VERY WARM (30-31 C) SEA
SURFACE TEMPERATURES. THE INITIAL POSITION IS PLACED WITH HIGH
CONFIDENCE BASED ON THE ANIMATED RADAR IMAGERY AND A SHORT
EXTRAPOLATION FROM THE MENTIONED AMSR2 IMAGE. THE INITIAL INTENSITY
OF 85 KTS IS ASSESSED WITH MEDIUM CONFIDENCE BASED ON THE AGENCY
DVORAK FIXES RANGING FROM T4.5-5.0.

INITIAL WIND RADII BASIS: PERSISTENCE FROM 121329Z METOP-C ASCAT
SCATTEROMETER DATA 

CURRENT STEERING MECHANISM: SOUTHWESTERN PERIPHERY OF A SUBTROPICAL
RIDGE CENTERED OVER SOUTHERN HONSHU

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T4.5 - 77 KTS
   RJTD: T4.5 - 77 KTS
   RCTP: T5.0 - 90 KTS
   KNES: T4.5 - 77 KTS
   CIMSS D-MINT: 71 KTS AT 121721Z
   CIMSS D-PRINT: 81 KTS AT 121900Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE
   VWS: 15-20 KTS
   SST: 29-30 CELSIUS
   OUTFLOW: MODERATE WESTWARD

ANALYSIS CONFIDENCE:
   INITIAL POSITION: HIGH
   INITIAL INTENSITY: MEDIUM
   INITIAL WIND RADII: MEDIUM

3. FORECAST REASONING.

SIGNIFICANT FORECAST CHANGES: THERE ARE NO SIGNIFICANT CHANGES TO
THE FORECAST FROM THE PREVIOUS WARNING.

FORECAST DISCUSSION: 16W IS FORECAST TO CONTINUE TRACKING
WEST-NORTHWESTWARD, ALONG THE SOUTHWESTERN PERIPHERY OF THE
SUBTROPICAL RIDGE THROUGHOUT THE ENTIRE FORECAST PERIOD. AN INITIAL
LANDFALL ALONG THE SOUTHEASTERN COAST OF TAIWAN IS EXPECTED TO
OCCUR AROUND 130300Z, JUST SOUTH OF TAITUNG. A SECOND LANDFALL IS
FORECAST TO OCCUR ALONG THE SOUTHEASTERN COAST OF CHINA JUST BEFORE
TAU 24. ERRATIC TRACK MOTION IS POSSIBLE AS THE VORTEX APPROACHES
TAIWAN DUE TO INTERACTION WITH THE CENTRAL MOUNTAIN RANGE.
REGARDING INTENSITY, 16W IS ANTICIPATED TO REACH A PEAK INTENSITY
RIGHT BEFORE LANDFALL OCCURS, WHICH IS UNABLE TO BE CAPTURED BY THE
JTWC WARNING DUE TO TEMPORAL RESTRICTIONS. 16W WILL THEN QUICKLY
WEAKEN AFTER MAKING LANDFALL IN TAIWAN. AFTER THE SECOND LANDFALL
IN CHINA, A RAPID DETERIORATION OF THE VORTEX WILL CAUSE 16W TO
DISSIPATE NO LATER THAN TAU 48 AS THE REMNANT VORTEX TRACKS FURTHER
INLAND.

MODEL DISCUSSION: NUMERICAL MODEL TRACK GUIDANCE IS IN VERY CLOSE
AGREEMENT WITH A 35 NM CROSS-TRACK SPREAD AT TAU 24 AND A 110 NM
CROSS-TRACK SPREAD AT TAU 48. THE JTWC TRACK FORECAST IS PLACED
CLOSE TO THE MULTI-MODEL CONSENSUS WITH HIGH CONFIDENCE. INTENSITY
GUIDANCE AGREES ON WEAKENING FROM TAU 12 ONWARD, BUT TO VARYING
DEGREES. HAFS-A AND GFS ARE THE QUICKEST TO WEAKEN THE SYSTEM WHILE
HWRF KEEPS THE SYSTEM STRONGER FOR A LONGER PERIOD. SPECIFICALLY,
AT TAU 24, HWRF HAS THE INTENSITY AT AROUND 65 KTS WHILE HAFS-A IS
AROUND 40 KTS. OVERALL, THE JTWC INTENSITY FORECAST IS PLACED
SLIGHTLY LOWER THAN CONSENSUS DUE TO THE EXPECTED RAPID WEAKENING
ONCE TERRAIN INTERACTION BECOMES A FACTOR.

FORECAST CONFIDENCE:
   TRACK 00-72 HR: HIGH
   INTENSITY 00-72 HR: MEDIUM//
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